Peculiar effects on the phase behaviour of hydroxypropylcellulose (HPC), obtained by the introduction of few methacrylic groups along the main chain, are discussed. In particular, the increase of mesophase stability in water, lowering the value of polymer concentration at which the anisotropic phase first appears with respect to underivatized HPC, as well as the decrease of stability of the anisotropic phase for neat polymers is illustrated and discussed in terms of substituent hydrophobicity.